Efficacy of low-dose and long-term oral acyclovir therapy after penetrating keratoplasty for herpes simplex heratitis

Purpose: To evaluate the efficacy of long-term and low-dose prophylactic oral acyclovir therapy in preventing the recurrence of herpetic infection and increasing graft survival in patients who undergo penetrating keratoplasty (PK) for herpes simplex keratitis (HSK). Patients and methods: Nineteen patients were included in the study, who underwent PK for herpes keratitis from July 1993 to November 1995, received oral acyclovir, and were followed at least 12 months. Group I included 12 patients with corneal scarring without perforation. These patients were free of inflammation for a mean of 4.1+/-2.2 months preoperatively, and received oral acyclovir 400 mg/day postoperatively for one year. Seven patients (Group 2) who developed corneal perforation due to necrotizing keratitis were treated with tissue adhesives, therapeutic contact lenses, and topical antiviral and oral acyclovir therapy for the resolution of active inflammation followed by PK after a mean of 3.8+/-2.1 months follow-up. They received oral acyclovir 400 mg/day postoperatively for one year in addition to standard postoperative therapy. The control group consisted of 16 patients (Groups 3 and 4) who underwent PK for herpes simplex keratitis and did not receive oral acyclovir. The indication for PK was corneal opacity and impaired visual acuity in It patients (Group 3) and corneal perforation in four (Group 4) Results: After an average of 25 months follow-up, there: was only one recurrence (8.3%) in Group I and two cases (28.6%) of herpetic recurrence in Group 2. Recurrence occurred at two months in one patient while he was taking oral acyclovir. Two of these recurrences followed the withdrawal of oral acyclovir therapy after one year of therapy. In contrast, in control groups there were four cases of herpetic recurrence (33.3%) in Group 3 and two (50%) in Group 4 after a mean of 30.5 months postoperative follow-up. In the study groups, a rejection episode was seen in three patients (15.8%) which was successfully treated with medical therapy. One patient from Group 2 developed bacterial keratitis which subsequently resulted in graft failure. All grafts remained clear in the other patients (94.7%) In the control groups, rejection developed in seven patients. Three rejection episodes were treated successfully, The other four developed graft failure in spite of intensive medical therapy. Conclusions: Our results suggest that postoperative oral acyclovir therapy is effective in preventing the recurrence of herpetic infection. However, the recurrence may develop after cessation of oral acyclovir therapy, especially in patients who underwent PK for corneal perforation due necrotizing HSK.